Columbia Professor Dickson Despommier has generated a fair amount of attention with his concept for "vertical farms," stacked, self-contained urban biosystems that would -- theoretically -- supply fresh produce for city residents year round. The New York Times showcased outlandish artists' conceptions of what such farms might look like. Colbert did his shtick. Twelve pilot projects are supposedly under consideration, in locations as far-flung as China and Dubai.

The concept has captured the imagination of at least the sliver of the public (including the editors at Worldchanging), who laments the enormous resource demands of our food production system and yearns for something easier on the land, easier on our aquifers, and less demanding of fossil fuels. Vertical farms seem to promise all that.

Promising, of course, is different than delivering. Construction requires a lot of energy. Keeping vegetables warm in winter requires a lot of energy. Recycling water requires a lot of energy. Generating artificial sunlight requires a lot of energy. In other words, the secret ingredient that makes vertical farms work (assuming they work at all) is boatloads of energy. No one seems to have actually done the math on the monetary and environmental costs of such a scheme, but they would no doubt be considerable.

Perhaps those costs pencil out (although they almost certainly do not), but the plausibility of the idea itself is in some ways beside the point. Whatever the merits of vertical farms, the enthusiasm with which this idea has been received suggests that we're becoming mightily reductive in the way that we think about sustainability. Local is good, the thinking goes, and more local is better.

Cities offer a lot of environmental benefits, at least compared to the alternatives. There are many reasons this is so, but they all spring from a fairly basic fact: cities are built for people. Lots of people, densely packed, sharing resources. Innovations that encourage or take advantage of that density are likely to make cities more sustainable. And innovations that undermine density have a lot of work to do to overcome their inherent environmental disadvantages.

New York City, for example, recently released an ambitious plan to slash municipal carbon emissions by almost two million metric tons per year. Fully 16% of total life cycle reductions will come from a new rail and barge network built for the express purpose of hauling garbage. No one will appear on The Colbert Report to plug the new garbage barges, but the system will eliminate five million vehicle miles per year. Less congestion, less noise, less air pollution, and less greenhouse gas emissions. New York's size and density make this project possible.

Urban vertical farms, on the other hand, fail miserably on this score. Land is one of the primary inputs for agriculture, which is why we don't expect to see corn growing in lower Manhattan. Such spaces are better reserved for people, mass transit, mass entertainment, and businesses that depend primarily on human capital.

Our collective confusion on this point seems to be most acute when the topic is food. We intuitively understand that it doesn't really make sense to manufacture, say, iPods in small factories scattered across hundreds of urban centers, even though iPods are consumed in just about every city in the world. We readily grasp that the economics wouldn't work out, and we probably even understand that such a scheme wouldn't help the environment. Efficiency benefits more than just the bottom line.

Efficiency is particularly important when it comes to housing humans. Farming surely does stress the land, but so does suburban sprawl. Suburbs mean more lawns and more roads, for starters. Environmentally speaking, it makes more sense to move another person into a city than it does to make way for a berry patch.

iPods and food differ in important ways. But they don't differ as completely as some advocates seem to hope, and it really can make sense to house people in one place and grow food in another. Our food production system is, at present, undeniably in need of repair, but that doesn't mean that tomatoes in skyscrapers are the logical end point to which we should strive. (Note also that urban farms, community gardens, green roofs, etc. may have a lot of things going for them, but they don't exist on a continuum with industrial agriculture in the same way that vertical farms aspire to.)

As the world's population booms, we need to keep to continue growing and greening our cities. And that means keeping the focus where it belongs: on people.

This post is the most articulate and acute critique of vertical farming that I have come across. I spent my last semester in college researching the various conditions and implications of vertical farming, treating it simply as a radical extension of urban agriculture. I started my research fairly optimistic, having read exciting reviews on Dr. Despommier's idea, yet as the work got deeper, so did my understanding of the vertical farm.

Vertical farming and urban farming, as you point out, are two different ideas. Economic angles have not been fully analyzed, and while the theories and technologies and research sounds sexy, we may not be ready for such a huge undertaking. Sure, the demographic statistics are frightening, but the end goal of our eco-agricultural rainbow should be something a little more personal. At this point, I can't imagine a vertical farm fitting that role.

You seem to be making a broad point about urban farming, not just vertical farms, and using that concept as sort of a quasi-absurdist conclusion to the whole "local food" ideal as it relates to city life. This provoked me to make some long comments about this more fundamental question that arises from discussions of community gardens and local farming, etc. These aren't meant to be pissy, only to sort of tease out the matter a bit.

1) Peri-urban agriculture is practiced around the world in major cities, particularly in booming third world megacities, and it isn't based on Western planning ideals. It's based on absolute necessity. That being said, it works enough to have at least mixed promotion by authorities in the UN.

2) Local agriculture is more appealing a concept than local production of ipods because while ipods are fun and cute, we need food to not die, in fairly regular infusions, and nonlocal agriculture is utterly dependent upon national-level transportation infrastructure- well maintained roads, canals, trains, etc. It's also dependent upon a majority of the buying population actually having money to spend on food. Neither of these are realistic options in most of the world. Giving food raw economic analysis as though it's a luxury item like an ipod discounts the necessity of steady supplies of nonlocal cheap food, which cannot be guaranteed for most of the world by any means.

3) In regards to Western metropoles with fairly well-established economic colonization of the countryside, you reasonably can presume a measure of food security in terms of major transit (unless we have a depression again). But there are pretty significant reasons to promote local agriculture even under these conditions, despite apparent economic logic.

I think the localization tendencies sell themselves short when they focus on the calculus of sustainability to promote the cause. That is definitely important, but of equal importance is sustainability in terms of political control. Do you want the most important inputs to your society to be based in local meshworks or to function at the behest of global commodity markets and transportation firms? It's as simple as that. A dose of local food production in theory offsets the confusion and chaos of larger market fluctuations, innocent enough for fancy toys but crippling when it comes to the basic needs of life.

Remember, economically it made sense for Mexico to import its corn from the US rather than maintain a dense patchwork of ejido lands as a buttress. That is until the US corn crop was a little lower, and everyone got into corn ethanol, and oil prices shot up. Suddenly people are starving and rioting over the price of tortillas.

This is the difference between a sort of basic, technocratic environmentalism and one more based in using ecological principles to inspire social policy. You know, like building meshworks and ecologies for the provision of basic needs, with significant overlaps and redundancies built in, instead of satisfying the basic demands of life with one system governed by a single logic.

Posted by: dj on 9 Aug 08

You can't link tortilla prices to ethanol, since white corn and yellow corn are two completely different things.

It has been proven that there are well funded PR campaigns to brainwash people into blaming ethanol for higher food prices when in fact it is the higher cost of energy (oil) that is the culprit. You are smarter than the average joe, so go to www.alcoholcanbeagas.com and get your facts straight!

Love the article, happy to see smart criticism of VF theory. My response got a bit on the long side, which I put up over here.

In essence, my response is this:

1. VF could find a productive role in non-urban environments that can't support traditional agriculture. Imagine groves of these farms making use of coastal or mountainous ecosystems to produce valuable crops year round. It would be difficult to develop and operate such projects and minimize the impact of construction and waste, but it could be done.

2. Like Alan said, we can't afford to subscribe to only one philosophy of production. Redundancies and supplements are needed.

3. Not all cities are NYC, and many smaller towns and cities in NA are more contiguous with rural areas than the major metropolises, making VF less disruptive and more viable for them.

4. The technology is getting better all of the time! VF's energy footprint is a major concern, but it will only get better, especially once projects have been completed and we learn what does and doesn't work.

Humble thoughts, but I'm excited about the possibilities. Debate like this can push an idea like VF to its greatest potential and I'm happy to see it spreading.

Your iPod comparison is, to put it plainly, wrong. It probably does make economic sense to ship a high value, very small object from factories around the world. What makes no sense is shipping a half gallon of organic milk from Oregon to NY like the one I saw yesterday. This is simply criminal yet because it is 'organic' those in my co-op don't think about the consequences of not buying local.
Otherwise a good piece. I thought that these urban farm towers were a hopeless idealistic academic exercise far removed from any practical considerations such as the value of the land and air space as residential real estate. If someone thinks supplanting a development that could make millions in relatively immediate profits with a farm is going to fly then they're smoking better stuff than me.

You seem to be making a broad point about urban farming, not just vertical farms, and using that concept as sort of a quasi-absurdist conclusion to the whole "local food" ideal as it relates to city life.

I am making a broad point, but it's not about urban farming or even agriculture. Rather it's about cities and what they're good for. As for the specific topics of vertical farms and urban farming, I guess I'd say this:

Vertical farms strike me as a bad idea for strictly practical reasons, but my opinion on the matter is pretty irrelevant. If you like the idea of vertical farms, then you should advocate for some form of carbon pricing (as I do). Then vertical farms will succeed (or fail) on their merits, taking into account both economic and environmental costs.

Various forms of urban farming strike me as a good idea, but I don't really place these initiatives on a continuum with agriculture. I also think city parks are a good idea, but I don't view them as a replacement for wilderness. It takes roughly an acre of land to support a human. There are 8 million people in New York, so you'd need a farm about 40 times the size of New York to support New York. And that's fine. Such a farm exists -- just not in New York.

Giving food raw economic analysis as though it's a luxury item like an ipod discounts the necessity of steady supplies of nonlocal cheap food

It does? I'd suggest the opposite. Food isn't a luxury good, so economic analysis matters all the more. The world wouldn't really suffer if iPod prices went up 50%. When grain prices do, people suffer a lot.

Martin says the iPod analogy is wrong, but I don't think we actually disagree at all. I concur that we shouldn't manufacture milk in factories in China and ship it to the U.S. because that would be an economically inefficient thing to do. In fact, it doesn't matter what I think about shipping milk from China -- the market has already spoken. Food is like iPods only in the general sense that the laws of pricing aren't magically revoked or superseded by the principle of localism. Florida really is a good place to grow oranges, and Denver really isn't. Likewise, cities are a great place to house people, but not such a great place to grow alfalfa. All I meant with the iPod analogy is that we seem really quick to disregard costs and benefits when the subject turns to food in a way that we aren't when the subject is more frivolous products.

A professor I know puts this really well: you can grow tomatoes on the North Pole if the price is right. That doesn't make it a good (or green) idea.

I like the idea presented in the article, but why so highly critical of the concept of vertical farms? If none exist, then how can they be so bad? Localization is a real problem, and shipping fruit and food thousands of miles across the US is a huge problem. Like you stated, New York can achieve 16% of their carbon reduction goal just by cutting out the fat from their garbage transportation.

The environmental impacts from suburbs may be the "real" problem, but that doesn't invalidate a partial solution. Bottled water in developing countries creates pollution costs money and is a logistical headache, but it's certainly better than dying of dehydration, even if the "real" problem is a factory 25 miles up river.

Vertical farming may be expensive to produce, and require a lot of energy, but could a skyscraper farm in downtown NYC really use more energy than a fleet of trucks driving in food from California and the Mid-West? Not to mention the initial costs of getting their diesel fuel to them from Iraq in the first place.

Point source consumption (localization), regardless of volume, can be better than pulling resources from all over the globe. Turning your brow on Vertical farming is a complete regression of your previous argument made about the efficiencies of density.

Posted by: Alan on 12 Aug 08

I really can't stress this enough: while I think vertical farming is a fairly hopeless idea -- not a partial solution but a non-solution -- my opinion about the value of any particular technology doesn't really matter. Let's put a price on carbon emissions and see what clever people can make work. (Of course, I also see a role for public funding of certain promising technologies, but vertical farms don't come even close to making the cut.)

I do stand by the broader point, though, that we have a tendency to get overly reductive about the nature of some of our environmental problems, which occasionally leads us to admire some not-very-helpful solutions. If "food miles" are the problem then maybe vertical farms are the answer. But food miles aren't really the problem -- rather, fossil fuel usage is, and there are much better ways to wring fossil fuels from the food supply chain than vertical farms.

Vertical farming may be expensive to produce, and require a lot of energy, but could a skyscraper farm in downtown NYC really use more energy than a fleet of trucks driving in food from California and the Mid-West?

Oh my, yes! Of course, there's a lot of middle ground between vertical farms and long-distance trucking, which is good news for all of us.

Glad to see this post, since this has gotten so much attention recently. I will open by saying that I agree with your VF skepticism, but not your main point. It is apparent that the excitement generated by 'radical' ideas - even ones that don't pencil out - can reshape our sense of what is possible. Granted, we need to know what makes sense before we start funding and building things, but ideas that inspire people to re-think our systems are still sorely needed.

A few thoughts:
if there are indeed pilot projects in the works, lets see how they work.

You are right that construction requires a lot of energy, especially since these are supposed to be huge and made entirely of glass. However, keeping vegetables warm in winter shouldn't require a lot of energy; it is difficult to keep soil warm, but water could be warmed by running it through in-house compost or just the greenhouse effect of the glass.

Recycling water also shouldn't require a lot of energy, since it needn't be potable, just fit for plants - a living machine on the bottom floor could clean water before it's pumped back to the top. Generating artificial sunlight would be, I think, the biggest stumbling block.

Finally, while these are supposed to be huge structures, capable of feeding 50,000 (we build stadiums in cities...), they cannot replace soil-based food production. But if they can offset some of it, within a given resource budget, they are part of the solution.

Posted by: justus on 13 Aug 08

Locally produced food that does not affect the ecosystem of this planet to a large extent, bad?

Closing the loop for production facilities makes eco*2 sense all over the world, why not with food? The energy factor is of course a big question but with energy coming from renewables and even 'on location' produced, is it really a problem?

As for the moving people into cities instead, yes that is very important BUT you can not make a urban system sustainable without taking into account a whole range of different aspects everything from culture and services to green spaces and health. I think locally produced food makes sense in this equation.

I agree with Justus, I think this could be a part of the solution, what we MUST remember that in a sustainable society or urban space there will be a host of solutions that contribute to the whole.

Placing these towers in a habour or industrial area for example within the city limits perhaps? you don't have to place it in the middle of downtown. If you live in a city were all the brownfields are already re-developed then it might be too costly to build such a structure?

Greenfields and virgin land is more and more the world over used for planting and urban sprawl. Radically reducing biodiversity all over the globe, fast! If we can find a solution, that currently might cost more, I think we are obliged to at least TRY it.
If not for anybody else then for our selves, we're perhaps not talking about future generations anymore, but the problems are becoming so acute it is our own hides that will be in the blender in a few years or decades.

I believe that vertical farming is at its infancy and while it does have its challenges at this stage, it offers incredible opportunities in the future. This is yet another area that alternative energy can really be utilized to its fullest potential. The vertical farm does have the potential in theory to be a completely sustainable environment once 'green' architectural design, economic feasibility, and agricultural technologies all fall into line... Like all things in life, first we dream, then we conceptualize, build, study & analyze, and improve, all the while engaged in constructive debates such as these.

Every time there is a new innovation there are important questions asked about it impact on our lives and our world... This is a good thing, however; I believe in this case it is imperative for vertical farming to be explored and perfected for future generations.

Why?
Because our population isn't going to get smaller.

It is highly likely that one day almost all of our land (and probably some water) will be cities. Not one big city but communities of cities packed back to back that stretch from sea to sea. Regardless of how this makes you feel, its a better option than seeing a large portion of a population perish from the planet.

For me, vertical farming offers a potentially sustainable, economical, environmental, healthy method of delivering a huge variety of fresh produce to local, urban populations and is a good companion (not a replacement, right now) to traditional farming methods.